Builds a defensible TAM/SAM/SOM market-sizing model with bottom-up and top-down triangulation and a low/base/high sensitivity range. Use when someone asks "how big is the market", "calculate my TAM", "size this opportunity", is preparing an investor deck market slide, or needs to defend a market number under diligence. Do NOT use for revenue projections of an existing business - use revenue-modeling instead.
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name: Market Sizing
description: Builds a defensible TAM/SAM/SOM market-sizing model with bottom-up and top-down triangulation and a low/base/high sensitivity range. Use when someone asks "how big is the market", "calculate my TAM", "size this opportunity", is preparing an investor deck market slide, or needs to defend a market number under diligence. Do NOT use for revenue projections of an existing business - use revenue-modeling instead.
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# Market Sizing
A market size number is only useful if it is defensible. Investors have seen a
thousand "100B TAM" slides and discount all of them. This skill builds a number
you can defend under questioning by showing your work.
## The Three Layers
- **TAM (Total Addressable Market)**: total spend if everyone who could buy,
did, at your price. The ceiling.
- **SAM (Serviceable Addressable Market)**: the slice you can actually reach
given product, geography, and segment.
- **SOM (Serviceable Obtainable Market)**: what you can realistically win in
3-5 years given competition and execution. The number that matters for
planning.
## Build Bottom-Up First
Bottom-up is the credible method; build it before you ever cite a top-down
analyst report.… load the full skill through Skill Me